In each of the questions given below, there are two statements marked as Assertion (A) and Reason (R). Mark your answer as per the codes provided below:
- Both A and R are true and R is the correct explanation of A.
- Both A and R are true but R is not the correct explanation of A.
- A is true but R is false.
- A is false but R is true.
- Both A and R are false.
- Assertion (A): When lightning strikes, the sound is heard a little after the flash is seen.
Reason (R): The velocity of light is greater than that of the sound. - Assertion (A): A ship rises as it enters the sea from a river.
Reason (R): The density of sea water is higher as compared to river water. - Assertion (A): Sprouting should not be done before consuming the grains.
Reason (R): Sprouting kills many vital vitamins. - Assertion (R): Alcohol rather than mercury is used in a thermometer to measure a temperature of 60oC.
Reason (R): Alcohol has a lower freezing point than mercury. - Assertion (A): Pipes carrying water often burst in cold countries during severe winter.
Reason (R): Water expands on freezing. - Assertion (A): An electric bulb makes a ‘bang’ when it is broken.
Reason (R): The air inside the bulb rushes out immediately on breaking. - Assertion (A): Salt is an ingredient used to cook food at higher altitudes.
Reason (R): Temperature is lower at higher altitudes. - Assertion (A): Carbon monoxide when inhaled causes death.
Reason (R): Carbon monoxide combines with hemoglobin. - Assertion (A): It’s colder on mountains than it is on plains.
Reason (R): When altitude decreases, so does the temperature. - Assertion (A): Inside the earth metals are present in molten state.
Reason (R): Earth absorbs the sun’s rays. - Assertion (A): AIDS does not have a vaccine.
Reason (R): The AIDS virus alters its genetic code. - Assertion (A): Clothes are not washed properly in hot water.
Reason (R): Hard water contains many minerals. - Assertion (A): In India, females have higher life expectancy than the males.
Reason (R): Females receive a better diet. - Assertion (A): Appendix is a vestigial organ in human body.
Reason (R): It does not participate in digestion. - Assertion (A): Himalayas used to lay under the sea.
Reason (R): Fossils of various marine creatures are traced on the Himalayas. - Assertion (A): Legumes revive the soil fertility.
Reason (R): Microbes in the root nodules of legumes fix the atmospheric nitrogen.
Answers
- 1 R provides the correct reason for A.
- 1 Due to higher density of sea water, the upthrust produced by the sea water on the ship is greater as compared to that produced by river water.
- 2 Diamond is hard due to its rigid three dimensional structure and so, it is used for cutting glass Refractive inbox of diamond is high and this gives is greater transparency and brilliance.
- 1 Mercury freezes at – 39°C, while alcohol freezes at a point far below – 100o C. So, alcohol is used to measure lower temperatures. Similarly, mercury boils at 357oC, while alcohol boils at 78°C. So, mercury is used to measure high temperatures.
- 1 During severe winters, water in the pipes freezes to ice and expands, resulting in bursting of pipes.
- 3 There is a vacuum inside the electric bulb. When the bulb breaks, air rushes in at great speed from all sides to fill the vacuum, thus producing a ‘bang’.
- 2 Due to decrease in pressure at higher altitudes, water boils much below 100oC so that the food does not get sufficient heat for being cooked. Salt increases the bed point of water.
- 1 Carbon monoxide, when inhaled, combines with haemoglobin of blood to form carboxy- haemoglobin which inhibits the transport of oxygen.
- 1 Higher above the sea level, temperature decreases at the rate of 1°C for every 165 metres of ascent making mountain peaks colder.
- 3 Inside the earth, the high temperature and pressure keep metals molten. The earth reflects the sun’s rays rather than absorbing them.
- 1 A vaccine contains the inactivated germs of the disease. But the AIDS virus changes its genetic code and so no vaccine has been invented for it.
- 2 In hard water, clothes do not get washed properly because hard water doesn’t form lather with soap. Having said that, hard water does contains many minerals.
- 5 In India, due to high birth rate and due to neglect, females have a lower life expectancy as compared to males and although females need a better diet, they do not receive
- 1 Appendix, an organ that once aided in the digestion of raw vegetable matter, is now considered a functionless organ in human body.
- 1 Himalayas are the young fold mountains that at one time are believed to lie inside the Tethys Sea. This is evident from the recovery of fossils of marine creatures on its peaks.
- 1 The root nodules of leguminous plants contain nitrogen fixing bacteria which absorb the atomspheric nitrogen and convert it into nitrogenous compounds useful for the plants reviving soil fertility.
